In the long term evolution (abbreviated as LTE) system, the control signaling which needs to be transmitted in the uplink includes an acknowledgement/negative acknowledgement (abbreviated as ACK/NACK) message, a scheduling request (abbreviated as SR), and information reflecting the downlink physical channel state (abbreviated as CSI), which information has three forms: channel quality indication (abbreviated, as CQI), pre-coding matrix indicator (abbreviated as PMI), and rank indicator (abbreviated as RI).
When the user equipment (abbreviated as UE) has no physical uplink shared channel (abbreviated as PUSCH), the above uplink control signaling is sent on the physical uplink control channel (abbreviated as PUCCH).
The LTE defines a plurality of PUCCH formats, including PUCCH format 1/1a/1b and format 2/2a/2b, wherein format 1 is used for sending the scheduling request SR from the UE, format 1a and 1b are used for feeding back a 1 bit ACK/NACK message and 2 bits ACK/NACK message respectively, format 2 is used for sending the channel state information (CSI) of the downlink and for simultaneously sending CSI and ACK/NACK message (when it needs to send two kinds of uplink control signaling in the same subframe) when the subframe uses an extended cyclic prefix, format 2a is used for sending CSI and 1 bit ACK/NACK message (when it needs to send two kinds of uplink control signaling in the same subframe), and format 2b is used for sending CSI information and 2 bits ACK/NACX message (when it needs to send two kinds of uplink control signaling in the same subframe). However, when the user equipment has a PUSCH for sending simultaneously, in order to ensure the single carrier property of the uplink, the uplink control signaling needs to be multiplexed on the PUSCH and sent together with the data. In this case, the feedback of the three forms of CSI (CQI/PMI and RI) can be periodic feedback and can also be aperiodic feedback, and Table 1: uplink physical channel corresponding to periodic feedback and aperiodic feedback, and the particular feedback is as shown in FIG. 1:
Periodic CQI reportingAperiodic CQI reportingScheduling modechannelchannelFrequencyPUCCHnon-selectiveFrequencyPUCCHPUSCHselective
In this case, as to CQI/PMI and RI which are fed back periodically, if the UE does not need to send uplink data, then the CQI/PMI and RI which are fed back periodically are transmitted on the PUCCH in the format of 2/2a/2b (PUCCH format 2/2a/2b), and if the UE needs to send uplink data, then the CQI/PMI and RI are sent on the PUSCH; and as to CQI/PMI and RI which are fed back aperiodically, they are only transmitted on the PUSCH, and it is provisioned that when it needs to feed back periodic and aperiodic CSI on the same subframe, the periodic CSI will be dropped and only aperiodic CSI will be fed back.
In order to meet the requirements of the International Telecommunication Union-Advanced (abbreviated as ITU-Advanced), the long term evolution advanced (abbreviated as LTE-A) system as the evolution standard of LTE needs to support larger system bandwidth (up to 100 MHz) and needs to be backward compatible with the existing standard of the LTE. On the basis of the existing LTE system, the bandwidth of the LTE system can be combined to obtain larger bandwidth, and this technology is referred to as carrier aggregation (abbreviated as CA) technology, which technology can improve the frequency spectrum utilization rate of the IMT-Advance system and relieve the lack of frequency spectrum resources, thereby optimizing the use of frequency spectrum resources.
In an LTE-A system which uses the carrier aggregation technology, the uplink bandwidth and downlink bandwidth can include a plurality of component carriers. When the base station has physical downlink shared channel (abbreviated as PDSCH) which will be scheduled to the UE on a plurality of downlink component carriers and when the UE has no PUSCH to send in the current subframe, the UE needs to feed back the ACK/NACK message corresponding to PDSCH of the plurality of downlink component carriers on PUCCH. Currently, in relevant art, one working assumption is that these ACK/NACK messages are sent in a UE-specific uplink component carrier; as to the SR information, the working assumption is that the UE only sends one SR and this SR information is sent in a UE-specific uplink component carrier; as to periodic CSI information, the working assumption is that the CSI information is sent in a UE-specific uplink component carrier. The above working assumptions indicate that at most only one uplink component carrier can send the PUCCH.
However, since the LTE-A system loosens the requirements on uplink single carrier property, the PUCCH and PUSCH are allowed to be sent simultaneously. Due to the introduction of carrier aggregation, the PUSCH can be sent on a plurality of carriers simultaneously. In this way, it may appear several situations that the PUSCH and PUCCH on the same carrier are sent simultaneously, and the PUSCH and PUCCH on different carriers are sent simultaneously, and the like. In this situation, in relevant art, no technical solution regarding how to send the uplink control signaling is disclosed, therefore, in the current LTE-A system, the base station and UE have no common understanding about where to send the uplink control signaling, causing that the uplink control signaling cannot be processed correctly.